Carbonate compounds are currently used as electrolyte solvents for non-aqueous batteries containing electrodes made from alkali metals, alkaline earth metals, or compounds comprising these metals, for example lithium ion batteries. Current lithium ion battery electrolyte solvents typically contain one or more linear carbonates, such as ethyl methyl carbonate, dimethyl carbonate, or diethylcarbonate; and a cyclic carbonate, such as ethylene carbonate. However, at battery voltages above 4.4 V these electrolyte solvents can decompose, which can result in a loss of battery performance. Additionally, there are safety concerns with the use of these electrolyte solvents because of their low boiling point and high flammability.
To overcome the limitations of commonly used non-aqueous electrolyte solvents, various fluorine-containing carboxylic acid ester electrolyte solvents have been investigated for use in lithium ion batteries (see, for example, Nakamura et al in JP 4/328,915-B2, JP 3/444,607-B2, and U.S. Pat. No. 8,097,368). Although these fluorine-containing carboxylic acid ester electrolyte solvents can be used in lithium ion batteries having high voltage cathodes, such as the 4.7 V LiMn1.5Ni0.5O4 cathode, cycling performance can be limited, particularly at high temperatures.
Despite the efforts in the art as described above, a need remains for electrolyte solvents, and compositions thereof, that will have improved cycling performance at high temperature when used in a lithium ion battery, particularly such a battery that operates at high voltage (i.e. up to about 5 V), or that incorporates a high voltage cathode.